This invention relates generally to process control networks and, more particularly, to systems and a method for automatic failover of redundant servers in a process control network.
At least some known process control networks include a plurality of HMI clients connected to a pair of redundant SCADA servers via Local Area Networks (LAN). One SCADA server is in control as an active server while the other SCADA server is in standby mode. The data between the SCADA servers are synchronized. When the active server fails or is disconnected from the network for various reasons, the standby SCADA switches to the active role. The plurality of HMI clients need to switch to the newly active SCADA server to query and process the process data with minimal interruption. One of the problems with redundant schemes is that each client needs to have a connection to the active SCADA server of the logical pair. In such known networks, to maintain continuous connection to the active SCADA server, a custom script or application running on each HMI client polls the status of the SCADA server pair and switches between them when the active connection failed. However, such polling increases the computational overhead of each of the HMI clients and causes increased traffic on the network. Additionally, managing custom scripts or applications at the HMI client introduces a probability of configuration errors and compatibility issues.